U.S. Pat. No. 4,046,634 discloses an assay for isoenzymes, including LDH isoenzymes, which employs ion exchange column chromatography to isolate a mixture of LDH.sub.1 and LDH.sub.2 isoenzymes which are then detected by conventional techniques such as the Wacker LDH method.
German Auslegeschrift No. 21 28 670 discloses a method for assaying for isoenzymes, including LDH isoenzymes by treating the test sample with a large excess of a specific antibody to either LDH.sub.1 or LDH.sub.5 isoenzymes so as to effect quantitative precipitation of the antigen-antibody complex. After incubation and centrifugation of the precipitated complex, the enzyme activity of the supernatant was determined by the method reported in Z. Klin. Chemie und Klin. Biochemie 8, 658 (1970).
Sussman et al., Journal of Biological Chemistry 243, 160 (1968) have described an assay for individual organ specific isoenzymes of human alkaline phosphate using a two step procedure. In the first step the specific antibody to the desired isoenzyme was reacted with the test sample and then in a subsequent step the antibody-antigen complex is precipitated with a second antibody (anti-.gamma.-globulin). After centrifugation the supernatant is tested for residual isoenzyme activity.
The use of a second antibody insolubilized on a solid support material in radioimmunoassay procedures is described in U.S. Pat. No. 4,048,298. The disclosure includes the use of second antibodies adsorbed to the surface of polymeric solid support materials.
U.S. Pat. No. 3,843,443 relates to a method of immobilizing proteins on a fluorocarbon polymer support. Included within the disclosed proteins are antibodies and the preferred polymer support material is polyvinylidene fluoride (Kynar-a trademark of the Pennwalt Corp.).